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Journal ArticleDOI

A delay-dependent anti-windup compensator for wide-area power systems with time-varying delays and actuator saturation

01 Jan 2020-IEEE/CAA Journal of Automatica Sinica (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 7, Iss: 1, pp 106-117
TL;DR: A delay-dependent anti-windup compensator is designed for wide-area power systems to enhance the damping of inter-area low-frequency oscillations in the presence of time-varying delays and actuator saturation using an indirect approach and maximizes the estimation of the region of attraction.
Abstract: In this paper, a delay-dependent anti-windup compensator is designed for wide-area power systems to enhance the damping of inter-area low-frequency oscillations in the presence of time-varying delays and actuator saturation using an indirect approach. In this approach, first, a conventional wide-area damping controller is designed by using H∞ output feedback with regional pole placement approach without considering time-varying delays and actuator saturation. Then to mitigate the effect of both time-varying delays and actuator saturation, an add-on delay-dependent anti-windup compensator is designed. Based on generalized sector conditions, less conservative delay-dependent sufficient conditions are derived in the form of a linear matrix inequality ( LMI ) to guarantee the asymptotic stability of the closed-loop system in the presence of time-varying delays and actuator saturation by using Lyapunov-Krasovskii functional and Jensen integral inequality. Based on sufficient conditions, the LMI-based optimization problem is formulated and solved to obtain the compensator gain which maximizes the estimation of the region of attraction and minimizes the upper bound of L2-gain. Nonlinear simulations are performed first using MATLAB / Simulink on a two-area four-machine power system to evaluate the performance of the proposed controller for two operating conditions, e.g., 3-phase to ground fault and generator 1 terminal voltage variation. Then the proposed controller is implemented in real-time on an OPAL-RT digital simulator. From the results obtained it is verified that the proposed controller provides sufficient damping to the inter-area oscillations in the presence of time-varying delays and actuator saturation and maximizes the estimation of the region of attraction.
Citations
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Journal ArticleDOI
TL;DR: In this article , a dynamic anti-windup compensator is designed for linear systems with time-varying state delay, input saturations and external disturbances, and sufficient conditions are established under which the state trajectories of the closed-loop systems are bounded and meanwhile the performance can be guaranteed.
Abstract: This paper considers the dynamic anti-windup design problem for linear systems with time-varying state delay, input saturations and external disturbances. A dynamic anti-windup compensator is first designed that is dependent on the upper bound of the time-varying delay. Then, using an augmented Lyapunov–Krasovskii functional, a distributed-delay-dependent sector condition, some advanced inequalities and some congruence transformations, sufficient conditions are established under which the state trajectories of the closed-loop systems are bounded and meanwhile, the performance can be guaranteed. The anti-windup compensator gain can be explicitly solved by means of linear matrix inequalities. For the case of constant delay, the corresponding result is also presented. Finally, two numerical examples illustrate the effectiveness and advantages of the proposed results.

16 citations

Journal ArticleDOI
TL;DR: The design of an H-based observer that simultaneously estimates both the sideslip angle and the roll angle of a vehicle for a networked control system, with networked transmission delay based on an event-triggered communication scheme combined with neural networks (NN).
Abstract: Nowadays, vehicles are being fitted with systems that improve their maneuverability, stability, and comfort in order to reduce the number of accidents. Improving these aspects is of particular interest thanks to the incorporation of autonomous vehicles onto the roads. The knowledge of vehicle sideslip and roll angles, which are among the main causes of road accidents, is necessary for a proper design of a lateral stability and roll-over controller system. The problem is that these two variables cannot be measured directly through sensors installed in current series production vehicles due to their high costs. For this reason, their estimation is fundamental. In addition, there is a time delay in the relaying of information between the different vehicle systems, such as, sensors, actuators and controllers, among others. This paper presents the design of an $${H}_{\infty }$$ -based observer that simultaneously estimates both the sideslip angle and the roll angle of a vehicle for a networked control system, with networked transmission delay based on an event-triggered communication scheme combined with neural networks (NN). To deal with the vehicle nonlinearities, NN and linear-parameter-varying techniques are considered alongside uncertainties in parameters. Both simulation and experimental results are carried out to prove the performance of observer design.

10 citations

Journal ArticleDOI
TL;DR: In this paper, a sliding mode control (SMC) approach is proposed to design a performance-based load frequency controller for interconnected power system (IPS) with time delay, and a sliding surface function is designed to enhance dynamic performance of the power system.
Abstract: This paper proposes a sliding mode control (SMC) approach to design $$H_{\infty }$$ performance-based load frequency controller for interconnected power system (IPS) with time delay. Incorporating an artificial delay, a sliding surface function is designed to enhance dynamic performance of the power system. Linear matrix inequality-based stabilization criterion is derived using Lyapunov–Krasovskii functional for multi-area power system. A novel SMC law is designed with artificial delay to drive the system trajectory into the predefined sliding surface. The applicability of the proposed controller is proved by considering a two-area time-delay IPS. Performance of the controller is verified from the simulation study of the time-delay IPS with proposed controller in MATLAB/Simulink. Then, the controller performance is verified in real time by using OPAL-RT OP4510 digital simulator.

8 citations

Journal ArticleDOI
TL;DR: In this paper, an improved free-matrix-based summation inequality is proposed to make full use of the improved inequality to bound the upper bounds of the difference Lyapunov-Krasovskii functional (LKF).
Abstract: The stability problem of discrete-time linear systems with interval time-varying delays is investigated in this paper. According to the latest summation inequality technique, an improved free-matrix-based summation inequality is proposed in this paper. In order to make full use of the improved inequality to bound the upper bounds of the difference Lyapunov-Krasovskii functional (LKF), an augmented LKF with some extra status information is constructed. A new delay-range-dependent stability criterion is derived in the form of linear matrix inequalities (LMIs) via the modified LKF approach. The criterion is less conservative than some existing results. Finally, some standard numerical examples are presented the effectiveness of the proposed approach.

8 citations

Journal ArticleDOI
TL;DR: This paper investigates coordinated design of multiple wide-area damping controllers (WADCs) for damping multiple inter-area oscillations considering communication delays in multiple control loop using modified IEEE 10-machine 39-bus power system.
Abstract: © 2021 The Authors. IET Generation, Transmission & Distribution published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology This paper investigates coordinated design of multiple wide-area damping controllers (WADCs) for damping multiple inter-area oscillations considering communication delays in multiple control loop. Two approaches have been investigated: the sequential approach which uses the stability criteria for single delay and design the WADC independently, and the coordinated approach which employs a less conservative and fast Lyapunov stability criterion for linear system with multiple delays to calculate delay margins simultaneously and coordinately design the multiple WADCs. The sequential approach cannot reveal the interaction among several WADCs loops with multiple delays and may lead to inaccurate delay margins, while the coordinated approach takes into account interactions of delays between different WADC control loops and can result in accurate delay stable region and relationship between delay margins and the WADC gains. Gains of WADCs are determined based on a trade-off between damping performance and delay margin. Case studies are based on the modified IEEE 10-machine 39-bus power system equipped with two FACTS devices and two WADCs. The feasibility and effectiveness of the proposed approach is verified by simulation studies.

7 citations

References
More filters
Journal ArticleDOI
TL;DR: This paper suggests the lower bound lemma for such a combination, which achieves performance behavior identical to approaches based on the integral inequality lemma but with much less decision variables, comparable to thosebased on the Jensen inequalityLemma.

2,248 citations


"A delay-dependent anti-windup compe..." refers background or methods in this paper

  • ..., the free-weighting matrix method [23] and integral inequalities [26]–[30]) have been proposed to deal with the integral terms....

    [...]

  • ...Remark 4: Many new integral inequalities (such as Wirtinger-based inequality [27], Free-matrix-based integral inequality [28], auxiliary function-based inequality [29], and Bessel-Legendre inequality [30]) are developed by introducing more terms to reduce the estimation gap of the Jensen integral inequality....

    [...]

Journal ArticleDOI
TL;DR: This paper addresses the design of state- or output-feedback H/sub /spl infin// controllers that satisfy additional constraints on the closed-loop pole location by derived in terms of linear matrix inequalities (LMIs).
Abstract: This paper addresses the design of state- or output-feedback H/sub /spl infin// controllers that satisfy additional constraints on the closed-loop pole location. Sufficient conditions for feasibility are derived for a general class of convex regions of the complex plane. These conditions are expressed in terms of linear matrix inequalities (LMIs), and the authors' formulation is therefore numerically tractable via LMI optimization. In the state-feedback case, mixed H/sub 2//H/sub /spl infin// synthesis with regional pole placement is also discussed. Finally, the validity and applicability of this approach are illustrated by a benchmark example.

2,036 citations

Journal ArticleDOI
TL;DR: An alternative inequality based on the Fourier Theory, more precisely on the Wirtinger inequalities is proposed and it is shown that this resulting inequality encompasses the Jensen one and also leads to tractable LMI conditions.

1,791 citations


"A delay-dependent anti-windup compe..." refers background or methods in this paper

  • ...L ∈ Rn×n,L = LT ≥ 0 τM ≥ τm ≥ 0 χ̇ : [−τM ,−τm]→ Rn×n Lemma 1 (Jensen’s inequality) [26]: For any constant matrix , two scalars , and vector function such that the following integration is well defined, it holds that:...

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  • ...To deal with the integral terms and of the LKF, one of the integral inequalities (Jensen’s inequality [26]) and the reciprocally convex approach [31] is used in order to reduce the complexity of the controller design by involving a lower number of decision matrix variables....

    [...]

  • ..., the free-weighting matrix method [23] and integral inequalities [26]–[30]) have been proposed to deal with the integral terms....

    [...]

  • ...Due to the simple LKF (25), in this work, we chose the Jensen integral inequality [26] out of the aforementioned integral inequalities....

    [...]

Book
26 Jun 2001
TL;DR: In this article, a control system with actuator saturation analysis and design is presented, in which a control law is designed a priori to meet either the performance or stability requirement.
Abstract: From the Publisher: "Control Systems with Actuator Saturation Analysis and Design examines the problem of actuator saturation depth. The overall approach takes into account the saturation nonlinearities at the outset of the control design. In the case that a control law is designed a priori to meet either the performance or stability requirement, it analyzes the closed loop system under actuator saturation systematically and redesigns the controller in such a way that the performance is retained while stability is improved. It also presents some related results on systems with state saturation or sensor saturation." "This book is a resource for professionals, researchers, practitioners, graduate students in control, electrical, and mechanical engineering, and all scientists and engineers interested in control systems with actuator saturation. Some first-year graduate courses in linear systems and multivariable control or some background in nonlinear control systems would greatly facilitate the reading of this book."--BOOK JACKET.

1,102 citations


"A delay-dependent anti-windup compe..." refers background in this paper

  • ...Various WADC design techniques are reported in the literature to guarantee the stability of the system by compensating the effect of time-delays [6]–[10]....

    [...]

  • ...In the literature, substantial research has been undertaken to model and study the effect of time-varying delays on power system stability ([6]–[10], and references therein), but very few works have been reported on the effect of actuator saturation on power system stability [17]–[21]....

    [...]

  • ...r 0 τM r t t+θ η̇ T (s)Zη̇(s)dsdθ τM η̇(t)Zη(t)− r t t−τ(t) η̇ T (s)Zη̇(s)ds r t−τ(t) t−τM η̇ T (s)Zη̇(s)ds r t−τ(t) t−τM η̇ T (s)Zη̇(s)ds Remark 3: In [8], [10], [22], the derivative of is often estimated as and the term is ignored, which leads to conservative estimation of the delay upper bound....

    [...]

Journal ArticleDOI
TL;DR: Two constructions of controllers that globally stabilize linear systems subject to control saturation are presented in terms of a "neural-network type" one-hidden layer architecture and a cascades of linear maps and saturations.
Abstract: We present two constructions of controllers that globally stabilize linear systems subject to control saturation. We allow essentially arbitrary saturation functions. The only conditions imposed on the system are the obvious necessary ones, namely that no eigenvalues of the uncontrolled system have positive real part and that the standard stabilizability rank condition hold. One of the constructions is in terms of a "neural-network type" one-hidden layer architecture, while the other one is in terms of cascades of linear maps and saturations. >

861 citations


"A delay-dependent anti-windup compe..." refers background in this paper

  • ...In the direct approach, the actuator saturation is considered at the beginning of control design [14], [15]....

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